Suggestions for fixing PVP
PVP's is one of the only sources of content many of the active players have going for them, and whilst the recent change to hardcore mode has helped for a time people have already started finding ways to bring around something equivalent to stimpack spamming.
There are still a plethora of weightless first aid and chem items that can be hoarded in the thousands with little to no effort from the user, allowing for older players to simply make it too difficult to compete.
Who grinds more wins, the highest health per second gained has simply replaced stimpack spam. Fights can still last upwards of an hour, the explosive meta is still there and the only way to deal with some people are groups of 6+ people with Annabelle's, Fatmans and Thump-Thump. With just that many people the sync gets worse, and the explosives just cause crashes.
Below I'll suggest some changes I believe will lower the time to kill players and make PVP a lot fairer.​

Forced normal difficulty
Hard-core removing stimpack spam was great, though in the end it just shuffled peoples hotkeys around. When people can still freely set their difficulty to Very-easy and are only forced to use hard-core, people simply don't take much damage. Hard-core without normal difficulty changes little. Changing difficulty alters damage multipliers when taking and giving out damage. Taking constant hits would simply be harder to deal with if normal difficulty was forced.​

Weight changes to consumables
There's nothing stopping anyone from gaining upwards of 100 health per second with low effort. Consumables such as Stimpacks and Super stimpacks are weightless, allowing you to farm them ad nauseam. Below is some information on consumables with and without weight.​

Concerns
With no cost on your weight you can half all incoming damage entirely with 50% Damage Resistance (DR), then use your damage threshold (DT) to remove the rest (DR comes before DT).
With little to no weight, you can heal what small remaining damage you took almost immediately.

Example
You have an explosive skill of 75 a strength stat of 5 (Annabelles skill/weight requirement for proper use) and are you using High Explosive missiles. They (should) do 473 damage. Using Slasher and Med-X the person you shoot only takes 236.5 damage. Their full condition Combat armor reinforced mark 2 (with the helmet) with a DT of 25 brings that to 211.5. In the 4 seconds you've taken to reload they've gained 300 health, still have 50% Damage resistance and a DT of 25, because they used super-stimpacks and stimpacks. With no weight cost.
Using a mix of the above consumables a player with a high enough level can make a party of 4 simultaneous HE explosive missiles trivial.​

Suggested weight changes

Stimpack - 0.2 lbs.
Weightless stimpacks can be farmed at a rate of 400+ in half an hour from Calamity, Jacobstown. With a weight of 0.2, 500 stimpacks would weigh 100 lbs. This forces you to consider the quantity of your medicals items alongside your ammo, weapons and armour.​

Super Stimpack - 0.4 lbs.
Weightless Super stimpacks whilst less common can be farmed at the exact same place as the stimpacks, and with enough many can be accrued with ease and some patience. With a weight of 0.4, 500 Super stimpacks would weigh 200 lbs. This will allow for less Super-stimpack use and will take from valuable space you could use for ammo, weapons and armour.

Desert Salad - 0.5 lbs.
The weight of 0.2 allows you to carry a massive 500 Desert salads at 100 lbs, for a large +21 Hit Point for 15s. If the weighed 0.5, carrying that much would take 250 lbs of your carrying capacity.

To summarise, all these above items are far too valuable in terms of health gain to be farmed so easily with so little weight cost.​

Removal of some merchants
Merchants can make getting some things a little too easy. Before Hard-core was implemented multiple people were accused of duplication when they simply farmed Calamity from Jacobstown, either farming caps or handing in Plasma grenades from Nellis AFB to buy stimpacks at a rate of 400 in 30 minutes on average. Below is the list of Merchants I think would balance the game to remove.

Calamity, Jacobstown
She enables people to farm massive amounts of Stimpacks, Super stimpacks, Med-X, Rad Away and Rad-X in a very short time frame.

Jack, Red-Rock Canyon Drug lab
He enables people to farm massive amounts of slasher, Hydra and other rare chems.

Great Khan armourer, South of Red-Rock Canyon
When people have 25mm and 40mm in the hundreds, it's normally from here. She sells stupidly high amounts of ammunition including these two ammo types in the literal hundreds. Making one visit to a merchant to get 300-500 25mm sounds balanced, right?

Vendortron 'Bob', Gun Runners
25 HE/HV and/or normal missiles you can get once every relog, farm caps or hand in Plasma grenades. Either way, he fuels an explosive meta most people don't find agreeable.​

Weight changes to certain ammo
This part is relatively brief, and something I'd suggest to withdraw people from the explosive spam. Whilst they help against bad sync, they cause frequent crashing.​